1. Field of the Invention
The present invention relates to a hinge device for a portable wireless terminal, and more particularly to a rotary type hinge device utilizing biaxial rotation, which enables the rotation of a folder, opened away from a terminal body of a portable wireless terminal, while rotating relative to the terminal body.
2. Description of the Related Art
Conventional portable wireless terminals can be categorized according to their shape. For example, there are bar type flip type and folder type terminals.
The bar type terminals comprise a main housing, data inputs and outputs and receiver and transmitter modules. In bar type terminals, there is a disadvantage in that the keypad, because it is used as data input, is always exposed, thereby causing it to malfunction. In addition, the bar type terminals are limited in their miniaturization due to required distance requirements between the receiver and transmitter modules.
Flip type terminals generally comprise a terminal body, a flip cover, and a hinge device adapted to rotatably couple the flip cover relative to the terminal body. The terminal body is mounted with data inputs and outputs and receiver and transmitter modules. The flip cover serves to cover the keypad when used as a data input, thereby preventing malfunctioning of the keypad, as described in reference to the bar type terminals. However, the flip type terminals are still limited in their miniaturization due to the required distance requirements between the receiver and transmitter modules.
The folder type terminals generally comprise a terminal body, a folder, and a hinge device adapted to rotatably couple the folder to the terminal body. The folder is adapted to be opened away from or closed to the terminal body according to its rotation. In a folded state, wherein the folder is in contact with the terminal body, the portable wireless terminal is in a call waiting mode, which prevents malfunctioning of the keypad when used for data input. When the folder is rotated and opened away from the terminal body, the portable wireless terminal is in a conversation mode, which ensures a sufficient minimum distance between transmitter and receiver modules. This configuration allows the portable wireless terminal, to be miniaturized. For these reasons, popularity of folder type terminals is increasing.
The hinge device provided in the flip type or folder type terminals is adapted to rotatably couple the flip cover or folder to the terminal body. However, if the flip cover or folder is opened away from the terminal body beyond a predetermined angle, the hinge device causes the flip cover or folder to be forced toward its open position without requiring any additional external force. Below the predetermined angle, the hinge device causes the flip cover or folder to be forced to come into close contact with the terminal body (i.e., closed).
The conventional hinge device for use in the flip type or folder type portable wireless terminals is disclosed in U.S. Pat. No. 6,292,980, issued to Yi, et al., the contents of which are incorporated herein by reference. The hinge device disclosed in said patent comprises a hinge cam and hinge shaft, which are formed with mountain-shaped portions or valley-shaped portions, respectively, and a hinge spring received in a hinge housing and adapted to urge the hinge cam to come into close contact with the hinge shaft. The hinge device is designed to open and close a flip cover or folder of a portable wireless terminal by means of circumferential curved surfaces of the mountain-shaped and valley-shaped portions and by the elastic force of the hinge spring.
Although mobile services have become increasingly diversified, and the number of functions the portable wireless terminals provide has increased, the conventional hinge device retains its function for simply causing the flip cover or folder of the portable wireless terminal to be opened away from, or closed to, the terminal body. The simple function and operation of the hinge device causes many limitations to modifying the specifications of the portable wireless terminal. For example, there are limitations in adding certain devices to the terminals for utilizing various other types of mobile services. In addition to the limitations of specification and design of the terminals, the conventional hinge device does not satisfy the aforementioned various mobile communication services' and customer's desires.